This invention relates to assays for analyte(s), e.g., antigens, in a sample such as a biological sample obtained from an animal. In particular, the invention relates to a method and device(s) for the detection of an analyte(s) utilizing binding moieties specifically targeting a selected analyte. More particularly, the analytes to be detected include infectious agents and/or components thereof.
Many types of assays have been used to detect the presence of various substances, often generally called analytes or ligands, in bodily samples. These assays typically involve antigen antibody reactions, ligand, anti-ligand, ligand receptor and utilize, synthetic conjugates comprising radioactive, enzymatic, fluorescent, or visually observable metal soluble tags, and specially designed reactor chambers. Most current tests are designed to make a quantitative determination, but in many circumstances all that is required is qualitative or positive/negative indication. Assays have been utilized to detect infectious agents, such as influenza.
Even the positive/negative assays must be very sensitive because of the often small concentration of the analyte of interest in the test fluid. False positives can also be troublesome, particularly with agglutination and other rapid detection methods such as dipstick and color change tests. Because of these problems, sandwich assays and other sensitive detection methods which use metal sols or other types of colored particles have been developed. These techniques have not solved all of the problems encountered in these rapid detection methods. Moreover, with the emergence of highly pathogenic agents such as influenza virus, there is a need to develop effective laboratory or point-of-care methods and systems that can effectively and accurately detect one or more infectious agents, such as influenza Types or strains within subtypes.
Influenza is commonly seen in local outbreaks or epidemics throughout the world. Epidemics may appear at any time and can occur explosively with little or no warming. The number of people affected can vary from a few hundred to hundreds of thousands. Epidemics may be short-lived, lasting days or weeks but larger epidemics may last for months. Although influenza is a mild disease in most individuals, it is life threatening to elderly, the very young or debilitated individuals. Epidemics are responsible for large losses in productivity. Therefore, there is a need to develop devices and methods to effectively detect what Types and subtypes of a pathogen, such as influenza, present in samples obtained from subjects in order to determine whether the infection is caused by a typical or expected subtype of Influenza (seasonal flu) or a subtype that is the causative agent of an epidemic or pandemic.
It is an object of this invention to provide a rapid, sensitive method for detecting analytes in a biological sample. Another object is to provide an assay which has high sensitivity and fewer false positives than conventional assays. A further object is to provide an apparatus or system for detection of low levels of analytes present in biological samples. Another object is to provide an assay system which involves a minimal number of procedural steps, and yields reliable results even when used by untrained persons. An additional object is to provide a system for testing infectious agents that provides results identifying one or more infectious agents in a matter of minutes. A further object provides a system where results on a testing implement are equally specific and sensitive for the target analytes, notwithstanding that results can be read one to several hours after completion of a reaction necessary to obtain a result. These and other objects and features of the invention will be apparent from the following description, drawing, and claims.